If you fish are deep bodied they have enough feed. Your rainbows will be more agressive than your brook trout, but they will probably die out in 3 to 4 years if you do not restock as it is doubtful they will be able to spawn successfully in the pond as the brook trout can.

Under optimum conditions brook trout can grow 1 1/2 inches per month.

You should be able to get stocking recommendations from you Ministry of Natural Resources for your pond size as not to overstock.

You could get optimum growth and larger maximum size by feeding, but you run the risk of enriching the pond and getting weed problems and other problems that go with that. If you have such a prolific insect population I would stick with staying in the guidelines for stocking densities and enjoy your pond!

If pigs could fly bacon would be harder to come by and there would be a lot of damaged trees.